The invention is directed to ammunition in which a portion of the projectile extends substantially aft into the ammunition case. The invention is particularly suitable for use with armor-piercing fin-stabilized discarding sabot (APFSDS) ammunition.
There exists a well-developed art in the field of APFSDS (including, inter alia, APFSDS-T (with tracer)) ammunition. APFSDS rounds have been developed for both rifled barrels (e.g., the 105 mm barrel of the relatively old M60 tank) and smoothbore barrels (e.g., the 120 mm barrel of the relatively new M1A2 tank). A rifled barrel or tube functions to spin-stabilize a projectile encased in the sabot, a principle utilized in a majority of modem weapons from handguns to large naval guns. An exemplary muzzle velocity is from about 1,375 to about 1,650 meters per second. A projectile exiting the muzzle of a rifled tube typically also has a relatively high spin rate. Once the projectile is free of the sabot, it relies on its aerodynamic fins for stability at a relatively low spin rate (e.g., about 70 revolutions per second (rps)). Upon discard of the sabot, the aerodynamic interaction of the projectile's fins with the air angularly accelerates the projectile to ultimately induce a desired low rate of spin (e.g., about 70 rps). With a smoothbore tube, upon discard of the sabot, the aerodynamic interaction of the projectile's fins with the air angularly accelerates the projectile to ultimately induce a desired low rate of spin (e.g., about 70 rps).